HAAT Question

That sounds fishy, no player can prevent your score from showing up.

The only possible thing that you might be trying to allude towards is damage wrap at phase ends, which is damaging being trapped in the previous phase because two people were finishing a phase at similar times. Only usually an issue if a guild is barely able to complete phases and they need to make every single point count to have a chance at beating the raid.

Right, it won't ever prevent your damage from appearing on the player list, but if your guild is really tight to get the raid done, it could be wasted damage because it wasn't all needed to kill the phase.

The only way damage overlaps is if one person finishes the phase and the other doesn't. If you both go partway into the next phase, I think the previous phase portion overlaps, but the two portions of the new phase should add up for that phase.